The present invention relates to an applicator for applying adhesive to a work piece, especially in edge glueing machines. In such applicators the adhesive may be supplied to the surface of a nozzle body through a row of applicator holes which may be opened and closed by a slide valve. In a first position of the slide valve the adhesive supply conduit is connected to the adhesive discharge holes. In a second position the holes are closed.
German Patent Application (DE-OS) No. 27 31 799 corresponding to U.S. Pat. No. 4,178,876 discloses such an applicator. The known applicator cooperates with a melting chamber in which a meltable adhesive in the form of a cylindrical cartridge or in the form of granular material is melted adjacent to a heatable facing melting wall forming a part of the melting chamber. There are holes in the melting wall and the adhesive is maintained under pressure for passing the molten adhesive through these holes into a nozzle body of the applicator proper. The applicator is provided with the adhesive discharge holes through which the adhesive is supplied to the narrow edge of a plate shaped work piece.
In the known melting and applicator device according to German Patent Application No. 27 31 799 corresponding to U.S. Pat. No. 4,178,876; issued on Dec. 18, 1979, it is possible that contaminations present in the meltable adhesive, such as small bodies not forming part of the adhesive or dirt particles, may be freed during the melting. These particles or bodies have a smaller specific weight than the adhesive and therefore have a tendency to travel into the adhesive supply conduit of the nozzle body. Once these contaminating elements are in the supply conduit, they have a tendency to clog the adhesive discharge holes, thereby preventing that the adhesive is properly applied to the work piece. If this happens, the bonding between the work piece and the respective edge strip is impaired.